It has become commonplace for personal audio devices worn on or about the head of a user in the vicinity of the ears and coupled via a cable to another device to acoustically output stereo audio provided by the other device to the ears such that each ear is provided with distinct left and right audio channels. Examples of such personal audio devices include headphones that may be coupled to another device such as a CD player, an entertainment radio, a television or a MP3 player, and include headsets that may be coupled to another device such as a two-way radio or telephone.
However, despite the widespread use of such personal audio devices, users of such personal audio devices often find themselves inconvenienced by the cable that couples such personal audio devices to another device. In essence, users find themselves effectively “tethered” to the other device to which such a personal audio device is coupled such that some degree of flexibility in moving about is lost. Users have often found it necessary to position themselves and/or limit their own movements to avoid putting sufficient tension on the cable to cause the coupling between such a personal audio device and the other device to which it is coupled to be broken, e.g., by pulling apart connectors at one end of the cable.
A commonplace solution to this inconvenience has been the use of wireless signaling between such personal audio devices and another device. However, such use of wireless signaling has drawbacks, including the frequent use of batteries with personal audio devices such that use of a personal audio device is limited by the power storage capacity of a battery. Further, issues of electromagnetic interference between devices may arise as a result of using at least some forms of wireless signaling that employ radio frequency transmissions.
Another solution to this inconvenience in the case of headsets having a pair of earpieces to acoustically output stereo audio and a communications microphone to enable two-way communications, is to enable the cable to be coupled to either of the earpieces. In this way, a user is provided with at least the flexibility to decide whether they wish to have the cable “tethering” them to another device from either the left side or the right side of the headset. To enable the coupling of the cable to either earpiece, existing known implementations of such headsets have both left and right audio channel conductors, along with a ground conductor, carried by a headband that connects the two earpieces. When the cable is coupled to the left earpiece, right channel audio and ground are conveyed through the headband to the right earpiece. Similarly, when the cable is coupled to the right earpiece, the left channel audio and ground are conveyed through the headband to the left earpiece.
Unfortunately, by having both left and right audio channel conductors carried within the headband, left channel audio is conveyed along with right channel audio to the right earpiece when the cable is coupled to the left earpiece, and right channel audio is conveyed along with left channel audio to the left earpiece when the cable is coupled to the right earpiece, despite the fact that the conveying both left and right channel audio from one earpiece to the other in each of these situations is entirely unnecessary. Indeed, in existing known implementations of such headsets, whichever one of the left and right audio channel conductors is rendered unnecessary (depending on which one of the earpieces the cable is coupled to) is also allowed to remain unterminated, thereby causing the unnecessary one of these conductors to act in a manner akin to an antenna, receiving and introducing electromagnetic interference into one or the other of the left and right audio channel.